Apparatus for raising and lowering a tennis court net

ABSTRACT

Apparatus for raising and lowering the net of a tennis court which is incorporated in the post supporting the net. The apparatus includes a hydraulically operable ram and cylinder device, the ram of which is connected to the cord of the net so that the net is raised when the ram is extended. The ram is extended by a manually operable pump. A valve biassed to the open position is located so that fluid pumped from a reservoir into the cylinder is returned to the reservoir through the valve. The valve is closed to trap fluid in the cylinder to enable the ram to be extended by insertion of appropriate coin in a coinoperable mechanism. Operation of the coin-operable mechanism starts a timing device which is operative to open the valve at a predetermined time, usually one hour, after the valve has been closed. When the valve is opened the ram retracts under the weight of the net and/or the effect of a spring to cause the net to be lowered.

United States Patent Rodwell et al. Feb. 29, 1972 [54] APPARATUS FORRAISING AND FOREIGN PATENTS OR APPLICATIONS LOWERING A TENNIS COURT NET213,749 '4/1924 Great Britain ..273/29 R [72] Inventors: John Rodwell,Homchurch; Harry Marsden, n nf d both f England Primary Examiner-StanleyH. Tollberg Attorney-Ostrolenk, Faber, Gerb & Sofi'en [73] AsslgneezTennis Unlimited Incorporated, New

York, 57] ABSTRACT [22] Filed: 9 Apparatus for raising and lowering thenet of a tennis court [21] Appl. No.: 882,607 which is incorporated inthe post supporting the net. The apparatus includes a hydraulicallyoperable ram and cylinder o 0 device, the ram of which is connected tothe cord of the net so Ffllelgll Appllmlion Priority Dita that the netis raised when the ram is extended. The ram is ex- Dec 9 1968 GreatBritain 58 340/68 tended by a manually operable pump. A valve biassed tothe open position is located so that fluid pumped from a reservoir Mar.26, 1969 Great Britain ..l5,778/69 into the cynnder is rammed to thereservoir through the valve- [52] U S CL 194/91. 273/29 BB The valve isclosed to trap fluid in the cylinder to enable the [51] 5/10 ram to beextended by insertion of appropriate coin in a coin- [58] Fie'ld search'273/29, 194/9 30 50 9 T operable mechanism. Operation of thecoin-operable mechanism starts a timing device which is operative toopen the valve at a predetermined time, usually one hour, after the [56]Reterences cued valve has been closed. When the valve is opened the ramUNITED STATES pATENTS retracts under the weight of the net and/or theeffect of a spring to cause the net to be lowered. 1,998,454 4/1935Gordon ..273/29.4 BB

Blanchet..

16 Claims, 4 Drawing Figures PATENTEBFEB 29 1972 SHEET 1 BF 3 ATTORNEY)PAIENTEDFEBZQ I972 SHEET 2 OF 3 APPARATUS FOR RAISING AND LOWERING ATENNIS COURT NET This invention relates to apparatus for raising andlowering a tennis court net and particularly to apparatus having controlmeans including a coin operated mechanism.

Such control means may be used with fluid pressure ram devicesassociated with equipment available for use by the public on payment ofa fee, the operation of the ram device placing a component of theequipment in a position enabling the equipment to be used. For example,in a tennis court, the ram may operate to move the tennis court net to aplaying position.

According to the present invention there is provided apparatus forraising and lowering a tennis court net, the apparatus including acoin-operable mechanism operable to place the apparatus in a conditionin which the net can be raised, and a timing device operative to causethe net to be lowered at a predetermined time after the apparatus hasbeen placed in said condition.

According to a preferred embodiment of the present invention theapparatus comprises control means for a fluid pressure ram deviceincluding a pump which, in operation, draws fluid from a reservoir anddelivers it to a ram cylinder to move the ram in a predetermineddirection, the ram cylinder being connected to the reservoir throughvalve means so that, only when the valve means is closed can the ram bemoved in said predetermined direction, the control means including acoinoperated mechanism, operation of which closes the valve, and atiming device operative to cause the valve to be opened at apredetermined time after it has been closed.

The movement of the ram in said predetermined direction may be movementin a direction to extend the ram.

The timing device may include a disc rotatable by a motor at apredetermined rate, the disc having means thereon engageable by apivotable lever to constrain the disc from movement, insertion of a coinenabling the lever to be moved to a second position to permit the discto be rotated, the lever reengaging the said means after a predetermineddegree of rotation of the disc, the lever being pivotally connected tosaid valve means so as to maintain the valve closed when the lever is insaid second position.

The means may comprise at least one notch formed in the periphery of thedisc, the notch being engageable by the lever so that the lever when inthe second position is in contact with the peripheral surface of thedisc. The disc or each notch may have associated therewith an associatedelement of magnetic material, a magnet being positioned so that when thenotch is engaged by the lever the associated element lies within themagnetic field of the magnet, the arrangement being such that when thelever is moved out of the notch by the operation of the coin-operatedmechanism, the effect of the magnet causes the disc to rotate so thatthe lever then abuts the peripheral surface of the disc adjacent to thenotch thereby to maintain the lever in the second position.

The motor may comprise a spring motor controlled by an escapementmechanism or alternatively may comprise an electric motor in which caseinsertion of a coin in the coinoperated mechanism may actuate a switchto supply electric current to drive the timing device, the timingdevice, when so driven, causing a current to be applied to means forclosing the valve. The means for closing the valve may be a solenoid,cnergization of which causes closure of the valve against a resilientbias.

A further valve may be provided, the further valve being normally biasedto the closed position and being openable manually to allow fluid toflow from the ram cylinder to the reservoir.

An embodiment of the present invention will now be described by way ofexample only with reference to the accompanying drawings, in which:

F IG. 1 shows a tennis post containing the control means and adapted toraise and lower the net of a tennis court,

FIG. 2 shows a part sectional view of part of the control mechanism,

FIG. 3 shows a reverse view of FIG. 2, and

FIG. 4 shows a part sectional view of part of the control systemillustrated in FIGS. 2 and 3.

The post 1 is intended to be used in public parks and the like havingtennis courts open to the public on payment of a fee, usually for apredetermined period. It is not always practical to have an attendantpresent and the post about to be described enables a revenue to beobtained in the absence of an attendant. Thus, an income may be obtainedfrom such facilities as tennis courts without the expenses of anattendants wages and other overheads.

The tennis post 1 has a tubular upstanding member 1 within which islocated a hydraulic ram and cylinder device 2 controlled by acoin-operated control unit shown generally at 3. The ram has a mainhousing containing a chamber 4 and a ram element 5 extendable withrespect to the character 4. The ram element 5 is connected to a piston(not shown) slidable in the chamber 4 in the housing in a conventionalmanner. A fluid reservoir 6 is also contained in the housing and amanually operable pump 7 is provided to enable fluid to be pumped underpressure from the reservoir 6 to the chamber 5 in the housing to therebymove the piston and extend the ram element 5. Fluid is returned from thechamber 4 to the reservoir 6 through a return system comprising a pipe8, a hydraulic junction box 9, a main control valve 10 and a furtherpipe 11. The control valve 10 controls the flow of fluid through thereturn system, the control valve 10 being normally biased to the openposition so that fluid pumped into the chamber 4 is free to return tothe reservoir 6 through the return system. If the valve is urged to theclosed position, the fluid pumped into the chamber 4 is trapped thereinand the ram 5 is thereby extended.

The housing containing the chamber 4 of the ram and cylinder device 2 issecured to the upper portion of the post and the extensible ram 5 isarranged to extend downwardly within the post. A tennis court netsupporting cord 12 is secured to the ram 5 and passes upwardly over apulley 13 located adjacent to the top of the post and then horizontallyacross the tennis court to a conventional post on the far side thereof.Thus when the ram 5 is extended the cord 12 is pulled downwardly by theram 5 and the net is raised to the correct position. The ram 5 isextended manually by the manually operable pump 7 when the control valve10 is closed by operation of the coin-operated mechanism, the valvebeing maintained in the closed position by a timing device 14, shown ingreater detail in FIGS. 2 and 3, for a predetermined period, usually 1hour.

The coin-operated control unit 3 has a selector arrangement of knowntype (shown in outline in FIG. 2 reference 15) to ensure the use of thecorrect coin. The selector arrangement 15 is mounted on a housing 16 ofthe control unit 3. A lever 17 is pivotally mounted on the housing 16 soas to pivot about an axis 18, the lever 17 carrying a cam follower 19 inthe form of a small roller rotatably mounted on the lever 17. The camfollower 19 is arranged to cooperate with notches formed in theperiphery of a timing disc 27. An edge face 20 of the pivotable lever 17is arranged to cooperate with an edge face 21 on a control lever 22mounted on the housing 16 so as to pivot about an axis 23. The edgefaces 20 and 21 are positioned adjacent a coin outlet 36 of the selectorarrangement 15 so that an appropriate coin, on leaving the selector,lodges between the edge faces, 20, 21, of the levers l7 and 22. Thecontrol lever 22 is biassed by a coil spring 24 away from the edge face20 of the lever 17, a control knob 25 being provided by which thecontrol lever 22 may be pivoted inwardly against the resilient bias. Thepivotable lever 17 .is biassed by a coil tension spring 26 so as to urgethe edge face 20 towards the control lever 22 and the cam follower 19into engagement with the periphery of the timing disc 27. The rotatabletiming disc 27 is formed of a nonmagnetic material such as a syntheticplastics material and has six notches 28 disposed equidistantly aroundits periphery. A series of magnetic elements 29, formed of soft iron,are disposed equidistantly about the disc adjacent the peripherythereof, each of the magnetic elements 29 being associated with arespective one of the notches 28. The magnetic elements 29 are rivetedto the timing disc 27. A magnet 30 is positioned adjacent to theperiphery of the disc in such a position that when the cam follower 19is located in a notch 28 the soft iron element associated with thatnotch lies within the magnetic field of the magnet 30 in such a way thatwhen the cam follower 19 is withdrawn from the notch, the magnetic forcecauses the disc 27 to rotate to align the element and the magnet 30 sothat the cam follower l9 abuts the peripheral surface of the disc 27adjacent to the notch and thus cannot fall back into the notch. The disc27 is mounted so as to be freely rotatable on a shaft 31. The disc 27 isrotatable by a spring motor 32 of known type which is controlled by aconvention escapement mechanism so as to cause the disc to rotate atpredetermined rate. The motor 32 is engageable with the disc 27 througha peg 33 which projects into an annular slot 34 formed in the disc.

The selector arrangement has an inlet 35 through which coins areinserted into the mechanism, an operative outlet 36 through which coinsmay pass to fall between the faces and 21 of the levers l7 and 22respectively and a reject outlet 37 through which rejected coins arereturned to the inserter. A collection box 38 is located below theoperative outlet 36 to collect coins which are not rejected.

As shown in FIG. 3 the pivotable lever 17 is connected to a furtherpivotable member 39 pivotable about the axis 18. The member 39 has twoarms, one arm 40 operating a counter 41 each time the lever 17 ispivoted to its second position where it abuts the periphery of thetiming disc 27, the second arm 42 abutting a control member 43 of themain control valve 10 so that pivotable movement of the arm 42 about theaxis 18 causes the control member 43 to move between an open and aclosed position. The arm 42 also operates an antistacking linkage 44which prevents more than one coin being held in the coin-operatedmechanism at a time. The linkage comprises a first member 45 slidablymounted on the housing 16 so as to be slidable longitudinally into andout of engagement with one end 46 of a further member 47 pivotallymounted on the housing so as to pivot about an axis 48. A projecting arm49 projects at right angles from the other end of the member 47 so as toengage part of the mechanism of the selector arrangement 15. Thus, whenthe pivotable lever 17 has been moved to its second position abuttingthe periphery of the timing disc 27 the arm 45 is moved to cause thepivotable member 47 to pivot clockwise as viewed in FIG. 3, so that theprojecting arm 49 moves part of the selector arrangement to a positionsuch that further coins inserted therein are automatically rejectedwhether they are appropriate coins or not.

The control lever 22 is coupled through a sliding connection 50 to alever 51 mounted on the housing 16 so as to pivot about a pivotableconnection 52, the lever 51 abutting a control member 53 of an adjustingvalve 54, the hydraulic junction box 9 being mounted on the adjustingvalve 54. The adjusting valve 54 is biassed to the closed position.

As shown in greater detail in FIG. 4, the junction box has an inlet port56 connected to the chamber 4 of the hydraulic ram device 2 through thepipe 8 an outlet port 57 leading to the main control valve 10, an outlet58 leading to the adjusting valve 54, and an outlet 59 leading to thereservoir 6. A pressure relief valve 60 is interposed in the pathbetween the inlet 56 and the outlet 59. The pressure relief valve 60comprises a ball 61 resiliently biassed into engagement with a valveseat 62 and is arranged to open when greater than a predeterminedpressure prevails in the chamber 4 of the hydraulic ram device 2.

The operation of the tennis post is as follows:

If the correct coin is inserted in the selector arrangement 15, the coinfalls from the coin operative outlet 36 and lodges between the faces 20and 21 of the levers 17 and 22 respectively. If the control knob is thenpushed in, the control lever 22 pivots against its resilient bias andthis motion is transmitted through the coin to the pivotable lever 17 tothereby cause the lever to pivot about the axis 18 against its abuttingthe periphery of the timing disc, the arm 42 is moved resilient bias.This pivotal movement of the lever 17 causes the follower 19 to bewithdrawn from the notch in which it is located. The timing disc 27 isthus free to rotate on its shaft, and due to the magnetic influence ofthe magnet 30 on the magnetic element associated with the notch, thedisc 27 is rotated slightly to align this element with the magnet 30.Thus, when the control knob 22 is released the control lever 22 returnsto its initial position under the action of its resilient bias while thepivotable lever 17 is urged by its resilient bias until the cam follower19 contacts the peripheral surface of the timing disc 27. Since the disc27 has been rotated slightly by the magnet the follower 19 abuts theperipheral surface adjacent to the notch in which it was located. Thepivotable lever 17 is thus located in its second position and the coinis free to fall from between the control lever 22 and the pivotablelever 17 into the collection box 38.

Since the timing disc 27 is not constrained from movement by thefollower engaging in the notch the spring motor 32 is then able torotate the disc 27. Since the magnet has already rotated the disc 27slightly, the drive peg 33 through which the disc is driven by thespring motor does not abut the end of the annular slot and, therefore,there is an initial period in which the motor 32 is rotating the peg butin which the disc does not move. However, as this is the same for everycycle it does not affect the accuracy of the time in which the disc isbeing rotated by the motor. When the peg 33 contacts the end of theannular slot 34 the disc 27 is rotated by the motor 32 until thefollower 19, which follows the peripheral surface of the disc 27 dropsinto the next notch thus preventing the disc from rotating further. Whenthe lever 17 is in its second position to a position in which itmaintains the control valve 10 in the closed position. Thus fluid may bepumped from the reservoir 6 into the chamber 4 of the ram and cylinderdevice 2 to extend the ram 5 to thereby raise the tennis net.

The fluid pressure generated in the chamber 4 is applied to the inletport 56 of the hydraulic junction box 9 but is prevented from passingback to the reservoir since the main control valve 10 is in the closedposition, and the adjusting valve 54 is normally biased to the closedposition. If greater than a predetermined pressure is generated in thechamber 4 by excessive pumping of the pumping handle 7, the ball 61 ofthe pressure release valve 60 is lifted from its seat by this pressureand the excess fluid is allowed to pass through the outlet port 59 backto the reservoir 6 to thus relieve the pressure.

1f the ram is extended to such an extent that the net is raised to alevel higher than that required, the control lever 22 may be pressed topivot the lever 51 to thereby open the normally closed adjusting valve54. When the adjusting valve is open hydraulic fluid flows from thechamber 4 in the device 2 through the inlet port 56 of the junction box9 and out of the outlet port 58 through the opened adjustment valve 54and hence to the reservoir 6. This release of fluid allows the ram 5 .tocontract slightly thus causing the net to be lowered.

At the end of the predetermined time the cam follower 19 drops in thenext notch preventing the disc 27 rotating further, and this causes thepivotable lever 17 to pivot to its first position causing the controlarm 42 to pivot away from the control member 43 of the main controlvalve 10 and the member 45 of the antistacking linkage 44 to thus enablethe main control valve 10 to return to the open position and theantistacking linkage 44 to return to its initial position. Thus, thecontrol valve 10 is opened to allow fluid to flow from the chamber tothe reservoir and the hydraulic ram 5 retracts, either under the weightof the net or other resilient means, to thereby move the net to alowered position.

in an alternative embodiment, it is envisaged that the timing device maybe an electric motor and in this case, an appropriate coin inserted inthe mechanism is arranged to contact a microswitch, actuation of themicroswitch causing electric current to be supplied from an electricalsupply to the timing device. Operation of the timing device causes anelectric current to be applied to a solenoid which controls theoperation of the main control valve. The control valve is normallybiassed to the open position by a spring.

An override switch is provided to override the electrical current fromthe timing device to the solenoid controlling the control valve toenable the control valve to be opened to enable the height of the net tobe adjusted as described previously.

The operation of this embodiment is as follows:

If the correct coin is inserted in the selector arrangement, the coinfalls to a position in which it actuates the microswitch. When theswitch is actuated electric current is supplied to the timing device.The timing device is arranged to supply electric current to a solenoidfor a predetermined period, usually 1 hour. The supply of electriccurrent to the solenoid energizes the solenoid which moves the maincontrol valve to a position in which the control valve is closed. Thus,by operating the manually operable pump the tennis court net may beraised to its raised position.

If the pump is pumped to an extent to raise the net above the desiredposition the override switch may be operated to deenergize the solenoidand thus open the control valve. This causes the net to be lowered.Release of the override switch causes the solenoid to be reenergized andthe control valve is closed again and the net is located in a new lowerposition. If the net is too low it may be raised in the usual way byoperation of the manually operable pump.

At the end of the period for which the solenoid is energized by thetiming device, the timing device is switched off, the solenoid isdeenergized and hydraulic control valve is opened to cause the net to belowered. The switching off of the timing device causes the microswitchto be reset so that no electric current is supplied to the timing deviceuntil a further coin is inserted in the coin-operated mechanism.

Although this invention has been described with respect to a tennis postit will be appreciated that the invention could equally well be appliedto all types of net such as those used on badminton courts and also toother equipment components such as the lighting sets provided overbilliard tables which are raised and lowered to an operating position.It will also be appreciated that the term coin'-operated mechanism mayinclude the use of tokens and the like and is not to be construed asbeing limited to the use of coins of the Realm.

We claim:

1. Control apparatus for moving a sports barrier such as a tennis net,or the like, in different directions, which apparatus comprises valvemeans;

a coin-actuated mechanism operably connected to said valve means to shutsaid valve means;

a fluid reservoir;

a pump;

means flowably connecting said reservoir and said pump, said pump beingoperable for producing fluid pressure;

means flowably connecting said pump to said valve means for supplyingfluid pressure thereto;

a fluid pressure ram in a ram cylinder actuated by said fluid pressure,said ram being operably connected with said barrier, said ram beingmovable in a predetermined direction to move said barrier in onedirection;

a timing device;

means connecting said timing device to said valve means, said timingdevice being operable to open said valve means at a predetermined timeafter said valve means have been shut, said open valve means beingadapted to bleed said cylinder of said fluid pressure thereby to causesaid ram to move in a direction opposite to said predetermineddirection, which opposite directional movement of said ram causes saidbarrier to move in a direction opposite said one direction.

2. Control means as claimed in claim 1, wherein said barrier includes asupporting rope element secured to said ram such that movement of saidram in said predetermined direction draws upon said rope to move saidbarrier in one direction and movement of said rarn in the oppositedirection moves said rope to cause said barrier to move in the oppositedirection.

3. Control means as claimed in claim 1 in which the movement of the ramin said predetermined direction is movement in a direction to extend theram.

4. Control means as claimed in claim 3 in which the timing deviceincludes a disc rotatable by a motor at a predetermined rate, the dischaving means thereon engageable by a pivotable lever to constrain thedisc from movement, insertion of a coin enabling the lever to be movedto a second position to permit the disc to be rotated, the leverreengaging the said means after a predetermined degree of rotation ofthe disc, the lever being operatively connected to said valve means soas to maintain the valve closed when the lever is in said secondposition.

5. Control means as claimed in claim 4 in which the means comprises atleast one notch formed in the periphery of the disc, the notch beingengageable by the lever so that the lever when in the second position isin contact with the peripheral surface of the disc.

6. Control means as claimed in claim 5 in which the or each notch mayhave associated therewith an associated element of magnetic material, amagnet having positioned so that when the notch is engaged by the leverthe associated element lies within the magnetic field of the magnet, thearrangement being such that when the lever is moved out of the notch byoperation of the coin-operated mechanism the effect of the magnet causesthe disc to rotate so that the lever then abuts the peripheral surfaceof the disc adjacent to the notch thereby to maintain the lever in thesecond position.

7. Control means as claimed in claim 6 in which the motor comprises aspring motor controlled by an escapement mechanism.

8. Control means as claimed in claim 6 in which the motor comprises anelectric motor.

9. Control means as claimed in claim 8 in which insertion of a coin inthe coin-operated mechanism actuates a switch to supply electric currentto drive the timing device, the timing device, when so driven, causing acurrent to be applied to means for closing the valve.

10. Control means as claimed in claim 9 in which the means for closingthe valve is a solenoid, energization of which causes closure of thevalve against a resilient bias.

11. Control means as claimed in claim 4 in which the motor is engageablewith the disc through a peg which projects into an annular slot formedin the disc.

12. Control apparatus as claimed in claim 1 in which a further valve isprovided, the further valve being normally biassed to the closedposition and being openable manually to allow fluid to flow from the ramcylinder to the reservoir.

13. Control means as claimed in claim 1 including a pressure reliefvalve by which the pressure generated by said pump is limited to apredetermined value.

14. Control means as claimed in claim 1 in which the coinoperatedmechanism includes means for preventing coins falling to an operativeposition while the said valve is closed by operation of thecoin-operated mechanism.

15. Control means as claimed in claim 1 in which the ram is adapted toraise and lower the net of a tennis court.

16. Control means as claimed in claim 13 in which the control means isincorporated in a tennis post adapted to support a net of a tenniscourt.

1. Control apparatus for moving a sports barrier such as a tennis net,or the like, in different directions, which apparatus comprises valvemeans; a coin-actuated mechanism operably connected to said valve meansto shut said valve means; a fluid reservoir; a pump; means flowablyconnecting said reservoir and said pump, said pump being operable forproducing fluid pressure; means flowably connecting said pump to saidvalve means for supplying fluid pressure thereto; a fluid pressure ramin a ram cylinder actuated by said fluid pressure, said ram beingoperably connected with said barrier, said ram being movable in apredetermined direction to move said barrier in one direction; a timingdevice; means connecting said timing device to said valve means, saidtiming device being operable to open said valve means at a predeterminedtime after said valve means have been shut, said open valve means beingadapted to bleed said cylinder of said fluid pressure thereby to causesaid ram to move in a direction opposite to said predetermineddirection, which opposite directional movement of said ram causes saidbarrier to move in a direction opposite said one direction.
 2. Controlmeans as claimed in claim 1, wherein said barrier includes a supportingrope element secured to said ram such that movement of said ram in saidpredetermined direction draws upon said rope to move said barrier in onedirection and movement of said ram in the opposite direction moves saidrope to cause said barrier to move in the opposite direction.
 3. Controlmeans as claimed in claim 1 in which the movement of the ram in saidpredetermined direction is movement in a direction to extend the ram. 4.Control means as claimed in claim 3 in which the timing device includesa disc rotatable by a motor at a predetermined rate, the disc havingmeans thereon engageable by a pivotable lever to constrain the disc frommovement, insertion of a coin enabling the lever to be moved to a secondposition to permit the disc to be rotated, the lever reengaging the saidmeans after a predetermined degree of rotation of the disc, the leverbeing operatively connected to said valve means so as to maintain thevalve closed when the lever is in said second position.
 5. Control meansas claimed in claim 4 in which the means comprises at least one notchformed in the periphery of the disc, the notch being engageable by thelever so that the lever when in the second position is in contact withthe peripheral surface of the disc.
 6. Control means as claimed in claim5 in which the or each notch may have associated therewith an associatedelement of magnetic material, a magnet having positioned so that whenthe notch is engaged by the lever the associated element lies within themagnetic field of the magnet, the arrangement being such that when thelever is moved out of the notCh by operation of the coin-operatedmechanism the effect of the magnet causes the disc to rotate so that thelever then abuts the peripheral surface of the disc adjacent to thenotch thereby to maintain the lever in the second position.
 7. Controlmeans as claimed in claim 6 in which the motor comprises a spring motorcontrolled by an escapement mechanism.
 8. Control means as claimed inclaim 6 in which the motor comprises an electric motor.
 9. Control meansas claimed in claim 8 in which insertion of a coin in the coin-operatedmechanism actuates a switch to supply electric current to drive thetiming device, the timing device, when so driven, causing a current tobe applied to means for closing the valve.
 10. Control means as claimedin claim 9 in which the means for closing the valve is a solenoid,energization of which causes closure of the valve against a resilientbias.
 11. Control means as claimed in claim 4 in which the motor isengageable with the disc through a peg which projects into an annularslot formed in the disc.
 12. Control apparatus as claimed in claim 1 inwhich a further valve is provided, the further valve being normallybiassed to the closed position and being openable manually to allowfluid to flow from the ram cylinder to the reservoir.
 13. Control meansas claimed in claim 1 including a pressure relief valve by which thepressure generated by said pump is limited to a predetermined value. 14.Control means as claimed in claim 1 in which the coin-operated mechanismincludes means for preventing coins falling to an operative positionwhile the said valve is closed by operation of the coin-operatedmechanism.
 15. Control means as claimed in claim 1 in which the ram isadapted to raise and lower the net of a tennis court.
 16. Control meansas claimed in claim 13 in which the control means is incorporated in atennis post adapted to support a net of a tennis court.